Question

Difficulty: HardIPv4 Static Routing

A network administrator needs to configure a floating static default route on a Cisco IOS router to serve as a backup to an existing OSPF-learned default route (Administrative Distance of 110). Place the operational steps in the correct sequential order to configure, validate normal operation, and verify failover behavior of this backup route.

  1. 1Identify the Administrative Distance of the primary routing protocol (OSPF AD 110) to determine a higher distance value for the floating static route.
  2. 2Enter global configuration mode using the `configure terminal` command.
  3. 3Execute the command `ip route 0.0.0.0 0.0.0.0 203.0.113.2 120` to configure the floating static default route.
  4. 4Execute `show ip route` in privileged EXEC mode to verify that the static route is not installed in the routing table while the primary path is operational.
  5. 5Simulate a primary link failure and execute `show ip route` to confirm the floating static default route populates the routing table.

Answer

The correct operational sequence begins by analyzing the primary protocol AD (110), navigating to global configuration mode, defining the floating static default route with a higher AD value (120), verifying that the route remains inactive in the routing table during normal operations, and finally testing link failover to confirm RIB insertion.
The workflow follows standard Cisco IOS network administration practices: planning parameters (AD selection), configuration entry, syntax application, baseline verification (confirming inactivity while primary is up), and failover validation (confirming activation when primary drops).

Step-by-Step Solution

1
Determine the primary route's Administrative Distance.
Identified OSPF AD as 110, requiring a floating static route AD > 110 (e.g., 120).
Floating static routes rely on a higher AD than the active routing source so they remain inactive until the primary route fails.
2
Access configuration mode.
Router prompt changes to `Router(config)#`.
Cisco IOS static route creation requires global configuration access.
3
Apply the static route configuration.
Configured `ip route 0.0.0.0 0.0.0.0 203.0.113.2 120`.
Defines a default route (`0.0.0.0 0.0.0.0`) pointing to next-hop `203.0.113.2` with an AD argument of `120`.
4
Verify initial routing table state.
Confirmed OSPF route is active in RIB and static route is absent.
Ensures the floating route does not preempt the primary dynamic path while the primary path is healthy.
5
Test path failover under fault conditions.
Static route `S* 0.0.0.0/0 [120/0] via 203.0.113.2` appears in `show ip route` output upon primary interface shutdown.
Validates proper failover functionality when the primary route is removed from the routing table.

Key Concept

Floating Static Route Lifecycle and Failover Validation
Estimated Time:2m 0s
Rate this question